外文翻译--机床设计

附录 1 Design of Machine Tool Designing starts with a need real. Existing apparatus may need improvements in durability, efficiency, weight, speed, or cost. New apparatus may be needed to perform a function previously. In the design preliminary stage, should allow to design the personnel fully to display the creativity, not each kind of restraint. Even if has had many impractical ideas, also can in the design early time, namely in front of the innovation the mentality. Usually, must propose several sets of design proposals, then perform the comparison. Has the possibility very much in the plan which finally designated, has used certain not in plan some ideas which accepts. When the general shape and a few dimensions of the several components become apparent, analysis can begin in earnest. The analysis will have as its objective satisfactory or superior performance, plus safety and durability with minimum weight, and a competitive cost. Optimum proportions and dimensions will be sought for each critically loaded section, together with a balance between the strengths of the several components. Materials and their treatment will be chosen. These important objectives can be attained only by analysis based upon the principles of mechanics, such as those of static for reaction forces and for the optimum utilization or friction； of dynamics for inertia, acceleration, and energy； of elasticity and strength of materials for stress and deflection； of physical behavior of materials； and of fluid mechanics for lubrication and hydrodynamic drives. The analyses may be made by the same engineer who conceived the arrangement of mechanisms, or un a large company, they may be made by a separate analysis division or research group. Design is a reiterative and cooperative process, whether done formally or informally, and the analyst can contribute to phases other than his own. Product design requires much research and development. Many Concepts of an idea must be studied, tried, and then either used or discarded. Although the content of each engineering problem is unique, the designers follow the similar process to solve the problems. Product liability suits designers and forced in material selection, using the best program. In the process of material, the most common problems for five (a) dont understand or not use about the latest application materials to the best information , (b) failed to foresee and consider the reasonable use material may (such as possible, designers should further forecast and consider due to improper use products. In recent years, many products liability in litigation, the use of products and hurt the plaintiff accused manufacturer, and won the decision), (c) of the materials used all or some of the data, data, especially when the uncertainty long-term performance data is so, (d) quality control method is not suitable and unproven, (e) by some completely incompetent persons choose materials. Through to the above five questions analysis, may obtain these questions is does not have the sufficient reason existence the conclusion. May for avoid these questions to these questions research analyses the appearance indicating the direction. Although uses the best choice of material method not to be able to avoid having the product responsibility lawsuit, designs the personnel and the industry carries on the choice of material according to the suitable procedure, may greatly reduce the lawsuit the quantity. May see from the above discussion, the choice material people should to the material nature, the characteristic and the processing method have comprehensive and the basic understanding. Finally, a design based upon function, and a prototype may be built. If its tests are satisfactory, the initial design will undergo certain modifications that enable it to be manufactured in quantity at a lower cost. During subsequent years of manufacture and service, the design is likely to undergo changes as new ideas are conceived or as further analyses based upon tests and experience indicate alterations. Sales appeal. Some Rules for Design In this section it is suggested that, applied with a creative attitude, analyses can lead to important improvements and to the conception and perfection of alternate, perhaps more functional, economical, and durable products. To stimulate creative thought, the following rules are suggested for the designer and analyst. The first six rules are particularly applicable for the analyst. 1. A creative use of need of physical properties and control process. 2. Recognize functional loads and their significance. 3. Anticipate unintentional loads. 4. Devise more favorable loading conditions. 5. Provide for favorable stress distribution and stiffness with minimum weigh. 6. Use basic equations to proportion and optimize dimensions. 7. Choose materials for a combination of properties. 8. Select carefully, stock and integral components. 9. Modify a functional design to fit the manufacturing process and reduce cost. 10. Provide for accurate location and noninterference of parts in assembly. The complete design of a machine is a complex process. The machine design is a creative work. Project engineer not only must have the creativity in the work, but also must in aspect and so on mechanical drawing, kinematics, engineering material, materials mechanics and machine manufacture technology has the deep elementary knowledge. One of the first steps in the design of any product is to select the material from which each part is to be made. Numerous materials are available to todays designers. The function of the product, its appearance, the cost of the material, and the cost of fabrication are important in making a selection. A careful evaluation of the properties of a. material must be made prior to any calculations. Careful calculations are necessary to ensure the validity of a design. In case of any part failures, it is desirable to know what was done in originally designing the defective components. The checking of calculations (and drawing dimensions) is of utmost importance. The misplacement of one decimal point can ruin an otherwise acceptable project. All aspects of design work should be checked and rechecked. The computer is a tool helpful to mechanical designers to lighten tedious calculations, and provide extended analysis of available data. Interactive systems, based on computer capabilities, have made possible the concepts of computer aided design (CAD) and computer-aided manufacturing (CAM). How does the psychologist frequently discuss the machine which the people adapt to operate. Design personnel basic responsibility is diligently causes the machine to adapt the people. This certainly is not an easy work, because certainly does not have to all people to say in fact all is the most superior operating area and the operating process. Another important question, project engineer must be able to carry on the exchange and the consultation with other concerned personnel. In the initial stage, designs the personnel to have to carry on the exchange and the consultation on the preliminary design with the administrative personnel, and is approved. This generally is through the oral discussion, the schematic diagram and the writing material carries on. If front sues, the machine design goal is the production can meet the human need the product. The invention, the discovery and technical knowledge itself certainly not necessarily can bring the advantage to the humanity, only has when they are applied can produce on the product, must first determine whether the people do need this kind of product. Grasps the project elementary knowledge to have to memorize some data and the formula is more important than. The merely service data and the formula is insufficient to the completely decision which makes in a good design needs. On the other hand, should be earnest precisely carries on all operations. For example, even if places wrong a decimal point position, also can cause the correct design to turn wrongly. Machinery design covers the following contents. 1. Provides an introduction to the design process, problem formulation, and safety factors. 2. Reviews the material properties and static and dynamic loading analysis, Including beam, vibration and impact loading. 3. Reviews the fundamentals of stress and defection analysis. 4. Introduces fatigue-failure design, which is commonly used in the design of rotation machinery. 5. Discusses thoroughly the phenomena of wear mechanisms, surface contact stresses, and surface fatigue. 6. Investigates shaft design using the fatigue-analysis techniques. 7. Discusses fluid-film an rolling-element bearing theory and application 8. Gives a thorough introduction to the kinematics, design and stress analysis of spur gears, and a simple introduction to helical, bevel, and worm gearing. 9. Discusses spring design including compression, extension and torsion springs. 10. Deals with screws and fasteners including power screw and preload fasteners. 11. Introduces the design and specification of disk and drum clutches and brakes. A good design personnel should dare to propose the new idea, moreover is willing to undertake the certain risk, when the new method is not suitable, use original method. Therefore, designs the personnel to have the patience, because spends the time and the endeavor certainly cannot guarantee brings successfully. A brand-new design, the request screen abandons absolutely many, knows very well the method for the people. Because many person of conservativeness does this certainly is not an easy matter. A mechanical designer should unceasingly explore the improvement existing product the method, should earnestly choose originally, the process confirmation principle of design in this process, with has not unified it after the confirmation new idea. 附录 2 机 床设计 设计开始之前就要想到机器的实际性，现存的机器需要在耐用性、效率、重量、速度或成本上加以改进。 在设计的初始阶段，应该允许设计人员充分发挥创造性，不受到任何约束。即使产生了许多不切实际的想法，也会在设计的早期，即在绘制图纸之前被改正掉。只有这样，才不至于阻断创新的思路。通常，还要提出几套设计方案，然后加以比较。很有可能在这个计划最后决定中，使用了某些不在计划之内的一些想法。 一般的当外型特点和组件部分的尺寸特点分析的透彻时，就可以全面的设计和分析。接着还要客观的分析机器性能和优越性，以及它的安全、重量 、耐用性，并且竞争力的成本也要考虑在分析结果之内。每一个至关重要的部分优化它的比例和尺寸，同时也要保持与其他组成部分相协调。也要选择原材料和处理原材料的方法。通过力学原理来分析和实现这些重要的特性，如那些静态反应的能量和摩擦力的最佳利用，像动力惯性、加速动力和能量；包括弹性材料的强度、应力和刚度等材料的物理特性，以及流体润滑和驱动器的流体力学。设计的过程是重复和合作的过程，无论是正式或非正式的进行，对设计者来说每个阶段都很重要。最后，以图样为设计标准，并建立将来的模型。如果它的测试时符合事先要求的，则再将对 初步设计进行某些修改，使它能够在制造成本上有所降低。产品的设计需要不断探索和发展。许多方案必须被研究、试验、完善，然后决定使用还是放弃。虽然每个工程学问题的内容是独特的，但是设计师可以按照类似的步骤来解决问题。 产品的责任诉讼迫使设计人员和公司在选择材料时，采用最好的程序。在材料过程中，五个最常见的问题为：（ 1）不了解或不会使用关于材料应用方面的最新最好的信息资料；（ 2）未能预见和考虑材料的合理用途；（ 3）所使用的材料的数据不完全或是有写数据不确定，尤其是当其性能数据长期不更新；（ 4）质量控制方法不适当和未 经验证；（ 5）由一些完全不称职的人员选择材料。 通过对上述五个问题的分析，可以得出这些问题是没有充分理由而存在的结论。对这些问题的研究分析可以为避免这些问题的出现而指明方向。尽管采用最好的材料选择方法也不能避免发生产品责任诉讼，设计人员和工业界按照适当的程序进行材料选择，可以大大减少诉讼的数量。 从以上的讨论可以看出，材料选择的人们应该对材料的性质，特点和加工方法有一个全面而基本的了解。 在随后生产和售后服务的几年中，要接受新观念的变化，或者由试验和经验为基础，进一步分析并改进。 一些设计规则 : 在本节中， 建议运用创造性的态度来替代和改进。也许会创造出更实用、更经济、更耐用的产品。 为了激发创造性思维，下列是设计和分析的建议和规则。前六个规则对设计者来说特别适用。 1、 要有创造性的利用所需要的物理性质和控制过程。 2、 认识负载产生的影响及其意义。 3、 预测没有想到的负载。 4、 创造出对载荷更为有利的条件。 5、 提供良好的应力分布和最小的刚度条件。 6、 运用最简单的方程来优化体积和面积。 7、 选择组合材料。 8、 仔细选择所备的原料和不可缺少的组件。 9、 调整有效的设计方案，以适应生产过程和降低成本。 10、规定好准确的位置条件为了使组件安装时不干 涉。 一台完整机器的设计是一个复杂的过程。机械设计是一项创造性的工作。设计工程师不仅在工作上要有创造性，还必须在机械制图、运动学、工程材料、材料力学和机械制造工艺学等方面具有深厚的知识基础。 任何产品在设计时第一步就是选择产品每个部分的构成材料。许多的材料被今天的设计师所使用。对产品的功能，它的外观，材料的成本、制造的成本做出必要的选择是十分重要的，对材料的特性必须事先做出仔细的评估。 仔细精确的计